Sleep disturbance and cognitive decline in individuals aged 25–44

Objective : to establish associations between the level of sleep disturbances (SD) and cognitive decline (CD; patterns of memory, attention, and executive functions) in individuals aged 25–44 years. Material and methods. In 2013–2016, a survey of a random representative sample of individuals aged 25–44 was conducted in one of the districts of Novosibirsk under the World Health Organisation's MOPSY (MONICA-psychosocial) programme. The level of SD and the state of cognitive functions (CF) were assessed in 713 people (325 men and 388 women; average age – 36.17±5.99 years) according to the criteria of the World Health Organisation's MOPSY (MONICA-psychosocial) programme. Standardised tests were used to assess CF. Results . In a random representative sample of individuals aged 25–44, the prevalence of sleep disorders was higher among women than men (46.4% versus 40.1%, respectively). At the same time, the subjective assessment of sleep by respondents was as follows: 'satisfactory' – 35.6% and 35.5%, “poor” – 10.3% and 4.3%, 'very poor' – 0.5% and 0.3% in women and men, respectively (χ 2 =10.482; df=4; p<0.033). It was found that when sleep was poor, men were able to name only 7.5476±1.20973 words during direct word recall in the 10-word memorization test of A.R. Luria, with satisfactory sleep – 7.5948±1.17612 words, and with good and very good sleep, they named 7.9956±0.84677 and 7.9923±0.94697 words, respectively (χ 2 =10.114; df=5; p=0.039). It was found that with poor sleep, men were able to view only 251.64±82.822 letters of the proofreading test in 1 minute, with satisfactory sleep – 288.36±73.961 letters. The best results for this indicator were achieved by men without SD, who were able to view 303.91±70.292 letters in 1 minute in the case of good sleep and 319.7±61.577 letters in the case of very good sleep (χ 2 =19.012; df=5; p=0.001). Women with sleep disturbances were able to recall 8.63±1.125 words during delayed reproduction of 10 words after an interfering task, while those with satisfactory sleep recalled 8.38±1.347 words. The best results in this test were achieved by women without SD, who were able to recall 8.76±1.387 words after good sleep and 8.69±1.398 words after very good sleep (χ 2 =12.264; df=5; p=0.015). Conclusion . A population study has established an association between sleep disturbances and cognitive decline (memory, attention and executive functions patterns) in individuals aged 25–44.